Cannot resolve the collation conflict - sql-server-2008

Question

I am getting the following error message.
Cannot resolve the collation conflict between "Latin1_General_CI_AI" and "SQL_Latin1_General_CP1_CI_AS" in the equal to operation.
I only get it when I place this code below in my WHERE clause.
WHERE Region IN (SELECT Token FROM dbo.getParmsFromString(#Region))
Now #Region contains all the values from my multi-select fields from SSRS.
Below is the code for the function that is used.
CREATE FUNCTION [dbo].[getParmsFromString]
(#String VARCHAR(MAX))
RETURNS #Parms TABLE
(
Token VARCHAR(MAX)
)
AS
BEGIN
IF CHARINDEX(',', #String) != 0
BEGIN
;WITH cte0(Token, List) AS
(
SELECT SUBSTRING(#String, 1, CHARINDEX(',',#String,1) - 1)
,SUBSTRING(#String,CHARINDEX(',',#String,1) + 1, LEN(#String)) + ','
UNION ALL
SELECT SUBSTRING(List,1,ISNULL(CHARINDEX(',',List,1) - 1,1))
,SUBSTRING(List,CHARINDEX(',',List,1) + 1, LEN(List))
FROM cte0
WHERE LEN(cte0.List) > 0
)
INSERT INTO #Parms (Token)
SELECT Token
FROM cte0
OPTION (MAXRECURSION 0)
RETURN;
END
ELSE
INSERT INTO #Parms
SELECT #String
RETURN;
END

Answer 1

Try changing
RETURNS #Parms TABLE
(
Token VARCHAR(MAX)
)
with
try changing RETURNS #Parms TABLE
(
Token VARCHAR(MAX) COLLATE DATABASE_DEFAULT
)
and
WHERE Region IN (SELECT Token FROM dbo.getParmsFromString(#Region))
with
WHERE Region COLLATE DATABASE_DEFAULT IN (SELECT Token FROM dbo.getParmsFromString(#Region))

Answer 2

Generally this type of error occurs when you try to compare the the data of different regions or when you compare data using a specific encryption with other data using a different encryption.
The most probable reason is that their tempdb is using the collation "SQL_Latin1_General_CP1_CI_AS" while the database is using "Latin1_General_CI_AS". As a result, temp objects are created under the collation "SQL_Latin1_General_CP1_CI_AS" and then fail to compare with database objects of the database which are using the collation "Latin1_General_CI_AS".
The easiest fix and also the one which would recommended would be to run the database on a server which was installed using collation "Latin1_General_CI_AS".
FYI. SQL collations("SQL_Latin1_General_CP1_CI_AS") are present in sql server for backward compatibility. When dealing with international data or databases using unicode and non unicode data, it is recommended to use windows collations ("Latin1_General_CI_AS").
You can change your database collation by:
use master
ALTER DATABASE "Your database"
COLLATE Latin1_General_CI_AS;
SELECT name, collation_name
FROM sys.databases;
and if needed you can also change the collation of "master" database i.e. rebuilding the database, for this go through to these links:
http://msdn.microsoft.com/en-us/library/dd207003(v=sql.100).aspx
http://sqlbuzz.wordpress.com/2011/08/20/how-to-rebuild-master-database-aka-rebuilding-sql-server-2008r2/
but make sure you backup all your database before doing this.